In the prior art, some electric sensors and FBG sensors are available for measuring the inclination. However, the range of FBG sensor generally could reach up to about 5 degrees, which is a lower accuracy in the order of minutes. Also these sensors were based on the effect of strain on the inclination which is involved with the issue of the resistance and lead to the considerable reducing of the measuring sensitivity and accuracy. Thereby a sensor with characteristics of long duration, high accuracy, no-wear and non-contact is needed to achieve the measuring function. The sensor in present invention is a Fabry-Perot sensor using the non-contact feature between optic fiber and reflecting surface to measure the inclination with quite high accuracy.